Nozzle structure for steam turbines

ABSTRACT

The nozzle structure of this invention includes a pair of nozzle blade supporting plates arranged in overlying relation. The plates are formed with an arcuate opening arranged in registration with a similar shaped passage in the wall of the steam chamber. The plates are formed with a recess in opposite side surfaces of the opening therein. Nozzle blades are positioned in the opening and have end portions extending into the recess. Spacers are also mounted in the recess between the end portions of the blades and are shaped to space the blades apart at the desired angle. The end portions of the blades and the spacers are clamped between plates and the plates are clamped against the wall of the steam chamber.

1 States Patent Czuszah 1 NOZZLE STRUCTURE FOR STEAM [11] 3,830,281 Sept, 17,1974

936,900 12/1955 Germany ..4l5/218 Primary Examiner-Henry F. Raduazo Attorney, Agent, or Firm-J. Raymond Curtin [5 7] ABSTRACT The nozzle structure of this invention includes a pair of nozzle blade supporting plates arranged in overlying relation. The plates are formed with an arcuate opening arranged in registration with a similar shaped passage in the wall of the steam chamber. The plates are formed with a recess in opposite side surfaces of the opening therein. Nozzle blades are positioned in the opening and have end portions extending into the re cess. Spacers are also mounted in. the recess between the end portions of the blades and are shaped to space the blades apart at the desired angle. The end portions of the blades and the spacers are clamped between plates and the plates are clamped against the wall of the steam chamber.

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sum 1 or 2 FIG I llllll 25 FIG. 4

SHEET 2 BF 2 NOZZLE STRUCTURE FOR STEAM TURBlINlES BACKGROUND OF THE INVENTION In one conventional form of a steam turbine nozzle structure, a one-piece member is machined to provide the steam passages. In another form, the nozzle structure is made up of nozzle blocks, rings and the like which are welded together to form an integral whole. The blocks are machined to provide passages extending at the desired angle for directing the steam to the blades or buckets on the turbine rotor. These structures are expensive to produce and usually cannot be modified; but if so, such modification is obtained by remachining the steam passages which usually involves an expense that makes the re-machining impractical.

This invention has as an object a turbine nozzle structure particularly economical to manufacture in which the steam passages can be conveniently and quickly modified at normal cost. The invention is also particularly advantageous in turbines requiring a large nozzle area due to the fact the turbine is operated with low steam pressure and high horsepower output is required.

SUMMARY OF THE INVENTION A pair of nozzle blade supporting plates are detachably secured to the wall of the steam chest or chamber, one plate overlying the other. The plates are formed with an opening in registration with the steam passage in the steam chest wall. The plates are formed to provide a recess in the opposite side surfaces of the opening. The recesses are enlarged transversely in the area inwardly of the side surfaces of the opening. A series of nozzle blades are arranged in the opening and have end portions extending into the recess. The blades are spaced apart and maintained at the desired angle by spacers disposed in the recesses intermediate the end portions of the blades. The blade ends and spacers are clamped between the plates and the plates to the steam chest wall by screw members.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a steam turbine embodying my invention;

FIG. 2 is a view taken on line 2-2, FIG. 1, with certain of the nozzle blades omitted;

FIG. 3 is an enlarged sectional view taken on line 33, FIG. 2, in the area thereof in which the nozzle blades are omitted;

FIG. 4 is an enlarged sectional view taken on line 44, FIG. 2, a portion of the nozzle blades being broken away to show the adjacent spacers in elevation;

FIG. 5 is a view taken on line 55, FIG. 4, with portions of the nozzle blades, spacers and supporting plates broken away showing the nozzle blade end portions and the spacers in section;

FIG. 6 is an isometric view of the nozzle blade; and

FIG. 7 is an isometric representation of a spacer.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a conventional form of turbine having upper and lower casing structures 10, 11 in which there is journaled the shaft 12 in bearing structures 13. Rotor discs 15, 17 are fixed to the shaft 12 and provided at their peripheries with a circular series of rotor blades or buckets 18, 19.

The casing is split horizontally on the axis of the shaft 12 providing the upper and lower casing sections 10, 11. The lower section 11 is formed with a steam chest or chamber 20 having a wall portion 21 formed with a passage 23. The nozzle ring structure 24 is mounted on the inner surface 25 of the wall 21 by screws 26, 27.

The nozzle structure consists of a pair of nozzle blade supporting plates 30, 31, illustrated as of semiannular form. The plates 30, 31 are each formed with an arcuate opening 33. With the plates .30, 31 bolted to the steam chamber wall 21, the arcuate openings 33 in the plates form a common arcuate opening arranged in registration with the steam passage 23. The plates 30, 31 are formed with recesses 34 at opposite side surfaces of the opening 33.

The inner portions of the recesses 34 are enlarged in a direction transversely of the opening 33, as at 40, 41, see FIG. 3. The inner enlargements 40, 41 form the recesses, T shaped in general configuration.

A series of nozzle blades 43 are arranged in the arcuate opening 33 in the plates 30,31. The blades 43 are formed with end portions 45 shaped complemental to the recesses in the plates 30,31. Intermediate the end portions 45 of the nozzle blades there are arranged spacers 50. The spacers 50 are also of a configuration comparable to the recesses at the opposite sides of the opening 33. The spacers 50 and the blade ends 45 are dimensioned such that when the blades and the spacers are assembled between the plates 30,31 and the plates secured to the wall 21 of the steam chest by the screws 26,27, the spacers and the ends of the blade are clamped tightly between the plates 30,31.

In FIG. 5, the spacers 50 at the ends of the Figure are shown in elevation in accordance with the section line 5-5, FIG. 4. The center portion of FIG. 5 is broken to the area of the enlargements 40,41, with the spacers 50 and blade ends 45 shown in section.

The configuration of the spacers 50 determines the spacing between the blades 43 and the angularity thereof in relation to the axis of the shaft 12. The recesses in the opposite side surfaces of the opening 33 are provided by simply forming grooves in the confronting sides of the plates 30,31. The nozzle blades 43 may be economically produced by being produced from rolled stock. The spacers 50 may be produced in like manner or fomied from powdered metal. Only the plates 30,31 need to be machined.

While I have described the preferred embodiments of my invention, it is to be understood that the invention is not limited thereto but may be otherwise embodied within the scope of the following claims.

I claim:

1. A nozzle structure for a steam turbine having a steam chamber with a wall formed with an arcuate passage communicating with the turbine cylinder, said nozzle structure comprising a pair of (inner and outer) nozzle blade supporting plates, one of said plates engaging said wall and the other plate overlying said first plate, said plates being formed with an arcuate opening arranged in registration with said passage, said plates being formed to provide a recess in the opposite side surfaces of said arcuate opening, a series of nozzle blades disposed in said opening, said blades extending across said opening and having end portions extending into said recesses, blade spacers mounted in said recesbeing arranged in registration with the grooves in said other plate.

3. A nozzle structure as set forth in claim 1 wherein said spacers and recesses are formed with interlocking means.

4. A nozzle structure as set forth in claim 1 wherein said blade ends are formed with means interlocking with said blade supporting plates. 

1. A nozzle structure for a steam turbine having a steam chamber with a wall formed with an arcuate passage communicating with the turbine cylinder, said nozzle structure comprising a pair of (inner and outer) nozzle blade supporting plates, one of said plates engaging said wall and the other plate overlying said first plate, said plates being formed with an arcuate opening arranged in registration with said passage, said plates being formed to provide a recess in the opposite side surfaces of said arcuate opening, a series of nozzle blades disposed in said opening, said blades extending across said opening and having end portions extending into said recesses, blade spacers mounted in said recesses intermediate said blade ends and removable clamping means to hold said plates in overlying registration to secure the blade ends and spacers therebetween and to secure the plates to said steam chamber wall and said clamping means consists of screws extending through said plates outwardly of said opening therein and threadEd into said chamber wall.
 2. A nozzle structure as set forth in claim 1 wherein said recess is formed by grooves formed in the confronting sides of said plates, the grooves in one plate being arranged in registration with the grooves in said other plate.
 3. A nozzle structure as set forth in claim 1 wherein said spacers and recesses are formed with interlocking means.
 4. A nozzle structure as set forth in claim 1 wherein said blade ends are formed with means interlocking with said blade supporting plates. 